Question

# 1. Motion of an object depends on its velocity only. True False 2. A car with...

1. Motion of an object depends on its velocity only.

True

False

2. A car with a mass of 2500 kg is traveling at a speed of 30 m/s due east. Choose the most appropriate answer to its momentum.

a. 30 m/s due east

b. 30 m/s

c. 75,000 kgm/s

d. 75,000 kgm/s due east

3. A car is traveling at 70 mph and then is involved in an accident with a head-on collision into a very solid wall. As a passenger in the car, which of the two scenarios will cause the greatest force upon you? Assume both scenarios have the same elapsed time and the car does not crumble during the collision.

a. An accident where the car comes to a stop at the wall.

b. An accident where the car bounces back off the wall.

4. A car with a mass of 2000 kg traveling at +20 m/s is hitting a wall head-on and bounces back in the same direction it came from with a speed of 20 m/s. The change in momentum is

a. -80,000 kgm/s

b. 0 kgm/s

c. +80,000 kgm/s

d. None of the above

5. A car with a mass of 2000 kg traveling at +20 m/s is hitting a wall head-on and bounces back in the same direction it came from with a speed of 20 m/s. If the impact time is 0.5 seconds, what is the net impact force during the collision.

a. -160,000 N

b. 0 N

c. +160,000 N

d. None of the above

6. A block is being pushed along a friction-less surface with a net force of +20 N. If the mass if the block is 40 kg, its acceleration is

a. -2 m/s^2

b. +0.5 m/s^2

c. +800 m/s^2

d. None of the above

7. An object traveling with a constant velocity can have a non-zero net force acting upon it.

True

False

8. Imagine you throw an object straight up in the air. At the very peak of the object's path, the net force acting upon the object is zero.

True

False

9. A person is pushing a crate with a mass of 20 kg across a floor with a force of +120 N. The crate experiences a frictional force with a magnitude of 40 N. What is the net acceleration of the crate?

a. -8 m/s^2

b. -4 m/s^2

c. +4 m/s^2

d. +8 m/s^2

10. A person is pushing a crate with a mass of 20 kg across a floor with a force of +120 N. The crate experiences a frictional force with a magnitude of 40 N. At the same time, a second person is pushing straight down onto the box with a force of 40 N. What is the net horizontal acceleration of the crate?

a. +2 m/s^2

b. +4 m/s^2

c. +6 m/s^2

d. None of the above

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